The present invention relates to a multisectional winding support comprising at least one inner and one outer form, as well as pins capable of being supplied in a controlled manner, for the winding of saddle-type coils comprising at least one string of winding wires, for use with deflection units of color-picture tubes. The saddle-type coils of a deflection unit serve to produce the magnetic fields effecting the deflection of the electron beams in color picture tubes.
Such saddle-type coils are named after their saddle shape and are constructed to have such a form so as to be self-convergent. Self-convergent saddle-type coils require no auxiliary currents in order to achieve convergence. Convergence is achieved when the accelerated electrons of all three electron beams, while being deflected in both the vertical and the horizontal direction, and owing to the temporal variation of the magnetic fields, exactly intersect at each point on the screen of the color picture tube.
The winding support comprises at least two members capable of being assembled, i.e., the inner and the outer form.
The inner form has the outwardly arched negative inner contour, and the outer form has the inwardly arched negative outer contour of the saddle-type coil to be wound between the inner form and the outer form.
The inner form of such a winding support or device only serves as the coilform as long as the coil is being wound. As long as the saddle-type coil is still positioned in the wind-support, the saddle-type coil is made self-supporting by way of bonding and/or heat bonding. After that, the saddle-type coil is removed from the spaced apart inner and outer forms of the winding support and, together with further coils, is assembled on a plastic sleeve or collar to form a deflection unit.
The winding of the individual winding wires in the coil is determinative of both the shape and the strength of the magnetic field to be produced by the coil. A slight deviation of the wire run from the rated value has an influence upon the magnetic field and, consequently, upon the deflection of the electron beams. This becomes noticeable in the form of convergence errors on the screen. Accordingly, a prerequesite for a useful winding technique is the good reproducibility of the position of the individual wires in the saddle-type coil.
This, however, is not easy to accomplish under mass-production requirements. Depending on the type of wire insulation, the wire lies differently to the already existing turns during the winding operation. The mechanical properties of the wire, such as the sliding ability, hardness of the wire, or the surface quality of the coilform are not always sufficiently constant. To a considerable extent, these properties depend e.g., on the temperature and the relative humidity.
An improved reproducibility of both the position and the run of the wires of the individual turns can be achieved by another conventional technique according to which the wire turns are wound directly onto a grooved winding collar. Considering that this fixed "coilform" of plastic is not removed, there is no need for the coil to be finally bonded or heat-bonded. The good reproducibility is safeguarded by placing the wires into the exactly defined grooves provided for on the winding collar, throughout its entire length.
One disadvantage of this conventional technique resides in the increased costs due to the precise manufacture of the collar and the long time required for performing the winding operation.